Nickel Alloy Nitinol · temper · default condition
Nickel Alloy Nitinol-O
Properties of the O condition, compared with the other Nitinol tempers.
Fully annealed at 700–850 °C, this general-purpose stock state offers the best ductility for further machining, forming and subsequent shape setting; room-temperature phase depends on composition.
What is Nitinol-O?
Nitinol-O is Nitinol in the O temper — fully annealed at 700–850 °C, this general-purpose stock state offers the best ductility for further machining, forming and subsequent shape setting; room-temperature phase depends on composition. Nitinol-O has a yield strength of 400 MPa (58 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 57% of nickel alloy grades. Elongation at break is 30% and the elastic modulus is 75 GPa (10.9 Msi). Nitinol-O has a density of 6.45 g/cm³ (0.233 lb/in³), lighter than 99% of nickel alloy grades. It melts at 1,300°C (2,372 °F).
Advantages
- Lightweight — 6.45 g/cm³ (0.233 lb/in³), better than 99% of nickel alloy grades
- Conducts heat well — 18 W/m·K (10.4 BTU/hr·ft·°F), better than 85% of nickel alloy grades
- High electrical conductivity — 1.7 % IACS, better than 76% of nickel alloy grades
Limitations
- Low stiffness — 75 GPa (10.9 Msi), worse than 100% of nickel alloy grades
- Low fracture toughness — 40 MPa·√m (36.4 ksi·√in), worse than 100% of nickel alloy grades
- High embodied carbon — 26 kg CO₂/kg, worse than 100% of nickel alloy grades
- Limited service temperature — 300°C (572 °F), worse than 99% of nickel alloy grades
- Difficult to weld — 35/100, worse than 77% of nickel alloy grades
Nitinol-O properties
Typical room-temperature values for Nitinol-O — 10 properties are specific to this condition; the rest are grade-level values shared by every Nitinol temper. Each bar shows where the value sits among the nickel alloy grades in FabDigit's library — further right is higher.
Physical3
Nitinol-O has a density of 6.45 g/cm³ (0.233 lb/in³), lighter than 99% of nickel alloy grades. It melts at 1,300°C (2,372 °F).
Mechanical11
Nitinol-O has a yield strength of 400 MPa (58 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 57% of nickel alloy grades. Elongation at break is 30% and the elastic modulus is 75 GPa (10.9 Msi).
Thermal5
Nitinol-O is rated for continuous service to 300°C (572 °F). It conducts heat at 18 W/m·K (10.4 BTU/hr·ft·°F), better than 85% of nickel alloy grades. Thermal expansion is 11 µm/m·K (6.11 µin/in·°F).
Electrical3
Nitinol-O conducts electricity at 1.7 % IACS, better than 76% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (82/100), better than 67% of nickel alloy grades.
Sustainability4
Producing a kilogram of Nitinol-O takes about 400 MJ of energy and emits 26 kg of CO₂ — more than 100% of nickel alloy grades. Typical recycled content is 5%.
Manufacturability8
Nitinol-O's machinability is not recommended (12/100, worse than 87% of nickel alloy grades); weldability fair (35/100); formability fair (45/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other Nitinol tempers and conditions
Nitinol is also supplied in 6 other conditions. The full side-by-side table is on the Nitinol overview.
- ODefaultFully annealed at 700–850 °C, this general-purpose stock state offers the best ductility for further machining, forming and subsequent shape setting; room-temperature phase depends on composition.400 MPa yield · 22 HRC
- Cold WorkedChoose 30–50% cold-drawn material with no final anneal for maximum strength and stiffness, 1300 MPa yield, in high-strength wire and spring blanks where memory or superelasticity is not needed.1,300 MPa yield · 38 HRC
- 60NiTiChoose the 60 wt% Ni variant, solution treated and hardened to HRC 55–62, for corrosion-resistant, non-magnetic bearings and cutting tools; it has no usable shape-memory function and only 3% elongation.1,100 MPa tensile
- SEPick the shape-set and aged austenitic state (Af ≈ 0–18 °C) for stents, guidewires and archwires needing 6–8% recoverable strain at room temperature; service is limited to 90 °C.480 MPa yield · 32 HRC
- SMUse the martensitic state (Af ≈ 45–95 °C) when the part is deformed softly at room temperature and recovers its shape on heating, as in thermal actuators, couplings and thermal switches.130 MPa yield · 210 HV
Working with Nitinol-O
Is Nitinol easy to machine?
Extremely difficult to cut because of rapid work hardening and low thermal conductivity; prefer wire EDM, sinker EDM, laser tube cutting and grinding. When turning or milling is unavoidable, use sharp coated carbide, low speed with heavy feed and abundant coolant.
Can Nitinol be welded?
Laser, resistance and inert-gas-shielded TIG welding of Nitinol to itself is feasible and retains part of the superelastic response. Direct welding to stainless steel or other dissimilar metals forms brittle intermetallic compounds — use a transition layer or mechanical/crimped joints instead.
Can Nitinol be formed, bent or molded?
Cold formability is good in the annealed martensitic condition, but springback is large. Set the final shape by constraining the part in a fixture at 450–550 °C for several minutes followed by a water quench; apply an intermediate anneal after 30–40% cold work.
What surface finishes work on Nitinol?
Chemical etching to remove black oxide followed by electropolishing produces a titanium-rich passive layer that reduces nickel release. Nitric acid passivation per ASTM F86 or colour anodizing for identification are options; avoid fluoride-bearing pickling solutions.
Nitinol chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| NiASTM F2063; ±0.1% Ni shifts transformation temp ~10 °C | 54.5 – 57 | 55.8 |
| C | ≤ 0.05 | — |
| Oas oxygen equivalent | ≤ 0.05 | — |
| H | ≤ 0.01 | — |
| Ncontrolled with O as oxygen equivalent | ≤ 0.05 | — |
| Fe | ≤ 0.05 | — |
| Cr | ≤ 0.01 | — |
| Cu | ≤ 0.01 | — |
| Co | ≤ 0.05 | — |
| Nb | ≤ 0.03 | — |
| Ti | balance | — |
Nitinol-O — frequently asked
What is Nitinol-O used for?
Nitinol-O is typically used for cardiovascular stents, guidewires and catheter components, orthodontic archwires, eyeglass frames, bone staples and compression implants and thermal actuators and switches. In short: shape memory medical wire.
What is the yield strength of Nitinol-O?
Nitinol-O has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 57% of nickel alloy grades. Strength varies by condition: see the 7 listed tempers.
Is Nitinol-O easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 87% of nickel alloy grades). Extremely difficult to cut because of rapid work hardening and low thermal conductivity; prefer wire EDM, sinker EDM, laser tube cutting and grinding. When turning or milling is unavoidable, use sharp coated carbide, low speed with heavy feed and abundant coolant.
Can Nitinol-O be welded?
With care — weldability is rated fair (35/100). Laser, resistance and inert-gas-shielded TIG welding of Nitinol to itself is feasible and retains part of the superelastic response. Direct welding to stainless steel or other dissimilar metals forms brittle intermetallic compounds — use a transition layer or mechanical/crimped joints instead.
What surface finishes work on Nitinol-O?
Chemical etching to remove black oxide followed by electropolishing produces a titanium-rich passive layer that reduces nickel release. Nitric acid passivation per ASTM F86 or colour anodizing for identification are options; avoid fluoride-bearing pickling solutions.
Can Nitinol-O be formed, bent or molded?
Cold formability is good in the annealed martensitic condition, but springback is large. Set the final shape by constraining the part in a fixture at 450–550 °C for several minutes followed by a water quench; apply an intermediate anneal after 30–40% cold work.
What is the maximum service temperature of Nitinol-O?
Nitinol-O is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Nitinol-O and Nitinol-SM?
O is the default condition — fully annealed at 700–850 °C, this general-purpose stock state offers the best ductility for further machining, forming and subsequent shape setting; room-temperature phase depends on composition. SM: use the martensitic state (Af ≈ 45–95 °C) when the part is deformed softly at room temperature and recovers its shape on heating, as in thermal actuators, couplings and thermal switches. Yield strength is 400 MPa in O versus 130 MPa in SM.
Can FabDigit make parts in Nitinol-O?
Yes — Nitinol-O is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM F2063 — Wrought Nickel-Titanium Shape Memory Alloys for Medical Devices — ASTM (2018)
- ASTM F2005 — Terminology for Nickel-Titanium Shape Memory Alloys — ASTM (2015)
- ASTM F2516 — Tension Testing of Nickel-Titanium Superelastic Materials — ASTM (2018)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Nitinol physical & mechanical property datasheets — Memry / SAES Smart Materials / Johnson Matthey Medical (2023)
- 60NiTi bearing alloy property reports — NASA Glenn Research Center (2014)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.